Techniques for enabling coarse-grained volume snapshots for virtual machine backup and restore

ABSTRACT

A technique of backing up a workload in a virtual environment includes identifying one or more files that are associated with the workload. One or more source volumes that include the one or more files are identified. A respective target volume is provisioned for each of the one or more source volumes identified. Only dirty blocks are copied (in a snapshot mode that prevents an update to the one or more source volumes during the snapshot mode) from each of the one or more source volumes to its respective target volume. The one or more dirty blocks are then copied from each target volume to a backup medium.

BACKGROUND

The present disclosure generally relates to techniques for enablingcoarse-grained volume snapshots for virtual machine backup and restoreand, more specifically, to techniques for enabling coarse-grained volumesnapshots for virtual machine backup and restore while minimizingperformance impact and virtual disk footprint.

In general, cloud computing refers to Internet-based computing whereshared resources, software, and information are provided to users ofcomputer systems and other electronic devices (e.g., mobile phones) ondemand, similar to the electricity grid. Adoption of cloud computing hasbeen aided by the widespread utilization of virtualization, which is thecreation of a virtual (rather than actual) version of something, e.g.,an operating system, a server, a storage device, network resources, etc.A virtual machine (VM) is a software implementation of a physicalmachine (PM), e.g., a computer system, that executes instructions like aPM. VMs are usually categorized as system VMs or process VMs. A systemVM provides a complete system platform that supports the execution of acomplete operating system (OS). In contrast, a process VM is usuallydesigned to run a single program and support a single process. A VMcharacteristic is that application software running on the VM is limitedto the resources and abstractions provided by the VM. System VMs (alsoreferred to as hardware VMs) allow the sharing of the underlying PMresources between different VMs, each of which executes its own OS. Thesoftware that provides the virtualization and controls the VMs istypically referred to as a VM monitor (VMM) or hypervisor. A hypervisormay run on bare hardware (Type 1 or native VMM) or on top of anoperating system (Type 2 or hosted VMM).

Cloud computing provides a consumption and delivery model forinformation technology (IT) services based on the Internet and involvesover-the-Internet provisioning of dynamically scalable and usuallyvirtualized resources. Cloud computing is facilitated by ease-of-accessto remote computing websites (e.g., via the Internet or a privatecorporate network) and frequently takes the form of web-based tools orapplications that a cloud consumer can access and use through a webbrowser, as if the tools or applications were a local program installedon a computer system of the cloud consumer. Commercial cloudimplementations are generally expected to meet quality of service (QoS)requirements of consumers and typically include service level agreements(SLAs). Cloud consumers avoid capital expenditures by renting usage froma cloud vendor (i.e., a third-party provider). In a typical cloudimplementation, cloud consumers consume resources as a service and payonly for resources used.

The IBM® Storwize® V7000 system provides copy services features thatfacilitate copying volumes or logical unit numbers (LUNs). The Storwize®V7000 FlashCopy function transfers a point-in-time copy of a sourcevolume to a designated target volume. In its basic mode, the FlashCopyfunction copies the contents of a source volume to a target volume. Inthis case, any data that existed on the target volume is lost and isreplaced by the copied data. The FlashCopy function is sometimesdescribed as an instance of a time-zero (T0) copy technology. Althoughit is difficult to make a consistent copy of a dataset that isconstantly updated, point-in-time copy techniques facilitateconsistently copying datasets that are constantly updated.

If a copy of a dataset is created using a technology that does notprovide point-in-time techniques and the dataset changes during the copyoperation, the resulting copy may contain data that is not consistent.For example, if a reference to an object is copied earlier than theobject itself and the object is moved before it is copied, the copycontains the referenced object at its new location, but the copiedreference still points to the previous location. More advanced FlashCopyfunctions allow operations to occur on multiple source and targetvolumes. FlashCopy management operations are coordinated to provide asingle common point-in-time for copying source volumes to theirrespective target volumes. In this manner, the FlashCopy function may beused to create a consistent copy of data that spans multiple volumes.The FlashCopy function also allows multiple target volumes to be copiedfrom each source volume to facilitate creating images from differentpoints-in-time for each source volume.

When a volume is created, the volume can be designated as athin-provisioned volume with a virtual capacity and a real capacity. Thevirtual capacity is the volume storage capacity that is available to ahost. The real capacity is the storage capacity that is allocated to avolume from a storage pool. In a fully allocated volume, the virtualcapacity and real capacity are the same. In a thin-provisioned volume,however, the virtual capacity can be much larger than the real capacity.Each system uses the real capacity to store data that is written to thevolume and metadata that describes the thin-provisioned configuration ofthe volume. As more information is written to the volume, more of thereal capacity is used.

Thin-provisioned volumes can help simplify server administration. Forexample, instead of assigning a volume with some capacity to anapplication and increasing that capacity as the needs of the applicationchange, a volume can be configured with a large virtual capacity for theapplication, and the real capacity can be increased or decreased, asstorage requirements of the application change, without disrupting theapplication or server. However, input/output (I/O) rates that areobtained from thin-provisioned volumes can be slower than those obtainedfrom fully allocated volumes that are allocated on the same managed diskdue to the need to access and process the extra metadata describing thecontents of thin-provisioned volumes.

BRIEF SUMMARY

Disclosed are a method, a data processing system, and a computer programproduct (embodied in a computer-readable storage medium) for enablingcoarse-grained volume snapshots for virtual machine backup and restorewhile minimizing performance impact and virtual disk footprint.

A technique of backing up a workload in a virtual environment includesidentifying one or more files that are associated with the workload. Oneor more source volumes that include the one or more files areidentified. A respective target volume is provisioned for each of theone or more source volumes identified. Only dirty blocks are copied (ina snapshot mode that prevents an update to the one or more sourcevolumes during the snapshot mode) from each of the one or more sourcevolumes to its respective target volume. The one or more dirty blocksare then copied from each target volume to a backup medium.

The above summary contains simplifications, generalizations andomissions of detail and is not intended as a comprehensive descriptionof the claimed subject matter but, rather, is intended to provide abrief overview of some of the functionality associated therewith. Othersystems, methods, functionality, features and advantages of the claimedsubject matter will be or will become apparent to one with skill in theart upon examination of the following figures and detailed writtendescription.

The above as well as additional objectives, features, and advantages ofthe present invention will become apparent in the following detailedwritten description.

BRIEF DESCRIPTION OF THE DRAWINGS

The description of the illustrative embodiments is to be read inconjunction with the accompanying drawings, wherein:

FIG. 1 depicts a relevant portion of an exemplary cloud computing nodethat is configured according to an embodiment of the present disclosure;

FIG. 2 depicts a relevant portion of an exemplary cloud computingenvironment that is configured according to one embodiment of thepresent disclosure;

FIG. 3 depicts exemplary abstraction model layers of a cloud computingenvironment configured according to an embodiment of the presentdisclosure;

FIG. 4 is a diagram of a conventional snapshot mechanism in which foursnapshots are taken of an original/base virtual machine (VM);

FIG. 5 depicts a diagram of an exemplary process for performing asnapshot, according to an embodiment of the present disclosure, in whichas dirty blocks are written into an original logical unit number (LUN)or source volume blocks containing backup data are pushed to a snapshotLUN or target volume;

FIG. 6 is a flowchart of an exemplary process that implements techniquesfor optimizing backup workflows according to various embodiments of thepresent disclosure; and

FIG. 7 is a flowchart of an exemplary process that implements techniquesfor optimizing recovery workflows according to various embodiments ofthe present disclosure.

DETAILED DESCRIPTION

The illustrative embodiments provide a method, a data processing system,and a computer program product (embodied in a computer-readable storagemedium) for enabling coarse-grained volume snapshots for virtual machinebackup and restore while minimizing performance impact and virtual diskfootprint.

In the following detailed description of exemplary embodiments of theinvention, specific exemplary embodiments in which the invention may bepracticed are described in sufficient detail to enable those skilled inthe art to practice the invention, and it is to be understood that otherembodiments may be utilized and that logical, architectural,programmatic, mechanical, electrical and other changes may be madewithout departing from the spirit or scope of the present invention. Thefollowing detailed description is, therefore, not to be taken in alimiting sense, and the scope of the present invention is defined by theappended claims and equivalents thereof.

It is understood that the use of specific component, device and/orparameter names are for example only and not meant to imply anylimitations on the invention. The invention may thus be implemented withdifferent nomenclature/terminology utilized to describe thecomponents/devices/parameters herein, without limitation. Each termutilized herein is to be given its broadest interpretation given thecontext in which that term is utilized. As may be utilized herein, theterm ‘coupled’ encompasses a direct electrical connection betweencomponents or devices and an indirect electrical connection betweencomponents or devices achieved using one or more intervening componentsor devices.

It should be understood that although this disclosure includes adetailed description on cloud computing, implementation of the teachingsrecited herein are not limited to a cloud computing environment. Rather,embodiments of the present invention are capable of being implemented inconjunction with any other type of computing environment now known orlater developed. Cloud computing is a model of service delivery forenabling convenient, on-demand network access to a shared pool ofconfigurable computing resources (e.g., networks, network bandwidth,servers, processing, memory, storage, applications, virtual machines,and services) that can be rapidly provisioned and released with minimalmanagement effort or interaction with a provider of the service. A cloudmodel may include at least five characteristics, at least three servicemodels, and at least four deployment models.

Cloud characteristics may include: on-demand self-service; broad networkaccess; resource pooling; rapid elasticity; and measured service. Cloudservice models may include: software as a service (SaaS); platform as aservice (PaaS); and infrastructure as a service (IaaS). Cloud deploymentmodels may include: private cloud; community cloud; public cloud; andhybrid cloud.

On-demand self-service means a cloud consumer can unilaterally provisioncomputing capabilities, such as server time and network storage, asneeded automatically without requiring human interaction with a serviceprovider. Broad network access means capabilities are available over anetwork and accessed through standard mechanisms that promote use byheterogeneous thin or thick client platforms (e.g., mobile phones,laptops, and personal digital assistants (PDAs)). Resource pooling meanscomputing resources of a provider are pooled to serve multiple consumersusing a multi-tenant model, with different physical and virtualresources dynamically assigned and reassigned according to demand. Inresource pooling there is a sense of location independence in that theconsumer generally has no control or knowledge over the exact locationof the provided resources but may be able to specify location at ahigher level of abstraction (e.g., country, state, or datacenter).

Rapid elasticity means capabilities can be rapidly and elasticallyprovisioned, in some cases automatically, to quickly scale-out and berapidly released to quickly scale-in. To the consumer, the capabilitiesavailable for provisioning often appear to be unlimited and can bepurchased in any quantity at any time. Measured service means cloudsystems automatically control and optimize resource use by leveraging ametering capability at some level of abstraction that is appropriate tothe type of service (e.g., storage, processing, bandwidth, and activeuser accounts). Resource usage can be monitored, controlled, andreported providing transparency for both the provider and consumer ofthe utilized service.

In an SaaS model the capability provided to the consumer is to useapplications of a provider that are running on a cloud infrastructure.The applications are accessible from various client devices through athin client interface such as a web browser (e.g., web-based e-mail). Inthe SaaS model, the consumer does not manage or control the underlyingcloud infrastructure (including networks, servers, operating systems,storage, or even individual application capabilities), with the possibleexception of limited user-specific application configuration settings.

In a PaaS model a cloud consumer can deploy consumer-created or acquiredapplications (created using programming languages and tools supported bythe provider) onto the cloud infrastructure. In the PaaS model, theconsumer does not manage or control the underlying cloud infrastructure(including networks, servers, operating systems, or storage), but hascontrol over deployed applications and possibly application hostingenvironment configurations.

In an IaaS service model a cloud consumer can provision processing,storage, networks, and other fundamental computing resources where theconsumer is able to deploy and run arbitrary software (which can includeoperating systems and applications). In the IaaS model, the consumerdoes not manage or control the underlying cloud infrastructure but hascontrol over operating systems, storage, deployed applications, andpossibly limited control of select networking components (e.g., hostfirewalls).

In a private cloud deployment model the cloud infrastructure is operatedsolely for an organization. The cloud infrastructure may be managed bythe organization or a third party and may exist on-premises oroff-premises. In a community cloud deployment model the cloudinfrastructure is shared by several organizations and supports aspecific community that has shared concerns (e.g., mission, securityrequirements, policy, and compliance considerations). The cloudinfrastructure may be managed by the organizations or a third party andmay exist on-premises or off-premises. In a public cloud deploymentmodel the cloud infrastructure is made available to the general publicor a large industry group and is owned by an organization selling cloudservices.

In a hybrid cloud deployment model the cloud infrastructure is acomposition of two or more clouds (private, community, or public) thatremain unique entities but are bound together by standardized orproprietary technology that enables data and application portability(e.g., cloud bursting for load-balancing between clouds). In general, acloud computing environment is service oriented with a focus onstatelessness, low coupling, modularity, and semantic interoperability.At the heart of cloud computing is an infrastructure that includes anetwork of interconnected nodes.

With reference to FIG. 1, a schematic of an exemplary cloud computingnode 10 is shown. Cloud computing node 10 is only one example of asuitable cloud computing node and is not intended to suggest anylimitation as to the scope of use or functionality of embodimentsdescribed herein. Regardless, cloud computing node 10 is capable ofbeing implemented and/or performing any of the functionality set forthherein. Cloud computing node 10 includes a computer system/server (orgenerally data processing system) 12, which is operational with numerousother general purpose or special purpose computing system environmentsor configurations. Examples of well-known computing systems,environments, and/or configurations that may be suitable for use withcomputer system/server 12 include, but are not limited to, personalcomputer (PC) systems, server computer systems, thin clients, thickclients, hand-held or laptop devices, multiprocessor systems,microprocessor-based systems, set top boxes, programmable consumerelectronics, network PCs, minicomputer systems, mainframe computersystems, and distributed cloud computing environments that include anyof the above systems or devices, and the like.

Computer system/server 12 may be described in the general context ofcomputer system-executable instructions, such as program modules, beingexecuted by a computer system. Generally, program modules may includeroutines, programs, objects, components, logic, data structures, and soon that perform particular tasks or implement particular abstract datatypes. Computer system/server 12 may be practiced in distributed cloudcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed cloud computing environment, program modules may be locatedin both local and remote computer system storage media including memorystorage devices.

As shown in FIG. 1, computer system/server 12 (in cloud computing node10) is illustrated in the form of a general-purpose computing device.The components of computer system/server 12 may include, but are notlimited to, one or more processors or processing units (including one ormore processor cores) 16, a system memory 28, and a bus 18 that couplesvarious system components (including system memory 28) to processors 16.Bus 18 represents one or more of any of several types of bus structures,including a memory bus or memory controller bus, a peripheral bus, anaccelerated graphics port, and a processor or local bus using any of avariety of bus architectures. By way of example, and not limitation,such architectures include the industry standard architecture (ISA) bus,the micro channel architecture (MCA) bus, the enhanced ISA (EISA) bus,the video electronics standards association (VESA) local bus, and theperipheral components interconnect (PCI) bus.

Computer system/server 12 typically includes a variety of computersystem readable media. Such media may be any available media that isaccessible by computer system/server 12, and includes both volatile andnon-volatile media, removable and non-removable media (also referred toherein as computer-readable storage devices). System memory 28 caninclude computer system readable media in the form of volatile memory,such as random access memory (RAM) 30 and/or cache memory 32 (alsoreferred to herein as computer-readable storage devices).

Computer system/server 12 may further include otherremovable/non-removable, volatile/non-volatile computer system storagemedia. By way of example only, storage system 34 can be provided forreading from and writing to a non-removable, non-volatile magnetic media(not shown and typically called a “hard drive”). Although not shown, amagnetic disk drive for reading from and writing to a removable,nonvolatile magnetic disk (e.g., a “floppy disk”), and an optical diskdrive for reading from or writing to a removable, non-volatile opticaldisk such as a CD-ROM, DVD-ROM or other optical media can be provided.In such instances, each can be connected to bus 18 by one or more datamedia interfaces.

As will be further depicted and described herein, memory 28 may includeat least one program product having a set (e.g., at least one) ofprogram modules that are configured to carry out the functions ofvarious disclosed embodiments. Program/utility 40, having a set (atleast one) of program modules 42, may be stored in memory 28 by way ofexample, and not limitation, as well as an operating system, one or moreapplication programs, other program modules, and program data. Each ofthe operating system, one or more application programs, other programmodules, and program data or some combination thereof, may include animplementation of a networking environment. Program modules 42 generallycarry out the functions and/or methodologies of embodiments of theinvention as described herein.

Computer system/server 12 may also communicate with one or more externaldevices 14 such as a keyboard, a pointing device, a display 24, one ormore other devices that enable a user to interact with computersystem/server 12, and/or any devices (e.g., network card, modem, etc.)that enable computer system/server 12 to communicate with one or moreother computing devices. Such communication can occur via input/output(I/O) interfaces 22. Still yet, computer system/server 12 cancommunicate with one or more networks such as a local area network(LAN), a general wide area network (WAN), and/or a public network (e.g.,the Internet) via network adapter 20. As depicted, network adapter 20communicates with the other components of computer system/server 12 viabus 18. It should be understood that although not shown, other hardwareand/or software components can be used in conjunction with computersystem/server 12. Examples, include, but are not limited to: microcode,device drivers, redundant processing units, external disk drive arrays,redundant array of inexpensive disk (RAID) systems, tape drives, anddata archival storage systems, etc.

With reference to FIG. 2, an illustrative cloud computing environment 50is depicted. As shown, cloud computing environment 50 comprises one ormore cloud computing nodes 10 with which local computing devices used bycloud consumers, such as, for example, personal digital assistant (PDA)or cellular telephone MA, desktop computer MB, laptop computer MC,and/or automobile computer system MN, may communicate. Nodes 10 maycommunicate with one another and may be grouped (not shown) physicallyor virtually, in one or more networks, such as private, community,public, or hybrid clouds as described herein, or a combination thereof.In this manner, cloud computing environment 50 can offer infrastructure,platforms and/or software as services for which a cloud consumer doesnot need to maintain resources on a local computing device. It should beunderstood that the types of computing devices MA-N shown in FIG. 2 areintended to be illustrative only and that computing nodes 10 and cloudcomputing environment 50 can communicate with any type of computerizeddevice over any type of network and/or network addressable connection(e.g., using a web browser).

With reference to FIG. 3, a set of functional abstraction layersprovided by cloud computing environment 50 (FIG. 2) is shown. It shouldbe understood that the components, layers, and functions shown in FIG. 3are intended to be illustrative only and embodiments of the inventionare not limited thereto. As depicted in FIG. 3, cloud computingenvironment 50 includes a hardware and software layer 60, avirtualization layer 62, a management layer 64, and a workloads layer66.

Hardware and software layer 60 includes various hardware and softwarecomponents. As one example, the hardware components may includemainframes (e.g., IBM® zSeries® systems), reduced instruction setcomputer (RISC) architecture based servers (e.g., IBM® pSeries®systems), IBM® xSeries® systems, IBM® BladeCenter® systems, storagedevices, networks and networking components. As another example, thesoftware components may include network application server software(e.g., IBM® WebSphere® application server software) and databasesoftware (e.g., IBM® DB2® database software). IBM, zSeries, pSeries,xSeries, BladeCenter, WebSphere, and DB2 are trademarks of InternationalBusiness Machines Corporation registered in many jurisdictionsworldwide.

Virtualization layer 62 provides an abstraction layer in which virtualentities (e.g., virtual servers, virtual storage, virtual networks(including virtual private networks), virtual applications and operatingsystems, and virtual clients are included. As previously discussed,these virtual entities may be accessed by clients of cloud computingenvironment 50 on-demand. The virtual entities are controlled by one ormore virtual machine monitors (VMMs) or hypervisors that may, forexample, be implemented in hardware and software layer 60,virtualization layer 62, or management layer 64.

Management layer 64 provides various functions (e.g., resourceprovisioning, metering and pricing, security, user portal, service levelmanagement, and SLA planning and fulfillment). The resource provisioningfunction provides dynamic procurement of computing resources and otherresources that are utilized to perform tasks within the cloud computingenvironment. For example, the resource provisioning function may beperformed for virtual machines (VMs) by one or more VMMs. The meteringand pricing function provides cost tracking (as resources are utilizedwithin the cloud computing environment) and billing or invoicing forconsumption of the utilized resources. As one example, the utilizedresources may include application software licenses.

The security function provides identity verification for cloud consumersand tasks, as well as protection for data and other resources. The userportal function provides access to the cloud computing environment forconsumers and system administrators. The service level managementfunction provides cloud computing resource allocation and managementsuch that required service levels are met. For example, the securityfunction or service level management function may be configured to limitdeployment/migration of a VM image to geographical location indicated tobe acceptable to a cloud consumer. The service level agreement (SLA)planning and fulfillment function provides pre-arrangement for, andprocurement of, cloud computing resources for which a future requirementis anticipated in accordance with an SLA.

Workloads layer 66 provides examples of functionality for which thecloud computing environment may be utilized. Examples of workloads andfunctions which may be provided from this layer include: mapping andnavigation; software development and lifecycle management; virtualclassroom education delivery; data analytics processing; and transactionprocessing.

VM or logical partition (LPAR) backup and restore is a key component ofcloud lifecycle management. Timely backup of VM virtual disks canprevent the loss of data in case of system-wide catastrophic failures.While maintaining a regular backup schedule is important, an overallbackup operation should ideally minimally impact workloads executing ina VM. Conventional disk snapshot is an efficient way to execute a backupon a live VM while minimizing backup time. However, conventional disksnapshot has some drawbacks that prevent effective usage in manyscenarios. For example, some conventional disk snapshot mechanisms(RedHat KVM snapshot, VMware VMDK snapshot, etc.) transform content ofan original disk into read-only content and create delta disks that cangrow in size.

With reference to FIG. 4, a diagram 400 illustrates a conventionalsnapshot mechanism in which four snapshots 404, 406, 408, and 410 aretaken of an original/base VM 402. In this example, original/base VM 402is established at time T0, and thereafter, read-only snapshots 404, 406,408 and 410 are taken of the changes to original/base VM 402 at timesT1-T4, respectively. Because read-only snapshots 404-410 do not containthe original content of original/base VM 402, but only changes to thatoriginal content, read-only snapshots 404-410 are commonly referred toas “delta disks.” More specifically, snapshot 404 includes the changesto VM 402 at time T1 and snapshot 406 includes the additional changes toVM 402 between times T1 and T2. Similarly, snapshot 408 includes theadditional changes to VM 402 between times T2 and T3 and snapshot 410includes the additional changes to VM 402 between times T3 and T4.

Although backup operations run relatively fast with conventionalsnapshot mechanisms, restoring a VM to a point-in-time can be a tedioustask. This is primarily because delta disks (e.g., read-only disks 404,406, 408, and 410) do not have the content of original/base disk (e.g.,read-only disk 402) and/or the content from prior delta disks. Torestore a VM to a point-in-time, snapshots are merged or block-pulledtowards an active disk. Unfortunately, merge operations can be I/Ointensive and adversely impact the performance of a hypervisor thathosts a VM, as well as the performance of workloads executing inside theVM.

Another class of snapshot technologies (e.g., IBM® Storwize® FlashCopy,Linux logical volume manager (LVM) snapshot, etc.) facilitate creatingsnapshots at a larger granularity. These snapshot approaches caneffectively clone an entire logical unit number (LUN) or source volume.However, the larger granularity snapshot technologies also require mergeoperations before restore is possible. Additionally, the largergranularity snapshot technologies are not immediately useful for thepurpose of VM snapshot, as virtual disks of a VM are often representedas individual files within a storage volume and are too fine-grained toleverage the larger granularity snapshot technologies. For example, asnapshot of an entire storage volume would unfortunately capture all thefiles on the volume even when a VM backup only requires a specific setof files on the volume.

In general, LVM snapshot incurs higher storage overhead than thedisclosed techniques because LVM snapshot does not employthin-provisioning and, as such, the actual storage space required afterthe snapshot is higher with LVM snapshot. In systems that implement acluster of machines with failover capability, managing LVM snapshotbecomes even more difficult and in some cases infeasible without anextra management layer. In addition, conventional hardware-assistedvolume snapshot technologies (e.g., IBM® Storwize® FlashCopy) haveoperated at the volume level, as contrasted with the file level.

According to the present disclosure, hardware-assisted volume snapshotis uniquely applied to create a thin-provisioned target volume tomaintain deltas (i.e., dirty blocks of specific files) from a sourcevolume. In this manner, the disclosed techniques leverage volume-basedsnapshot without the disk footprint of an entire volume. According tothe present disclosure, a new target (or shadow) volume may be mounteddirectly at any given time with contents appearing as they did at thetime of the snapshot, which enables specific files (such as virtualdisks, etc.) to be extracted from the volume-based snapshotasynchronously.

According to the present disclosure, techniques are disclosed thatprovide an efficient strategy for managing VM snapshots to optimizefuture restore operations while minimizing impact on hypervisor and VMperformance. In general, leveraging hardware-assisted volume snapshotsto backup individual files reduces I/O operations per second (IOPS)requirements for each operation, reduces a disk footprint required forbackup operations, and facilitates reduction in both backup and restoretimes. In one embodiment a hardware-assisted volume snapshot feature(such as FlashCopy, which is available on the StorWize® family ofstorage controllers, e.g., the V7000) is employed. According to one ormore embodiments, a temporary volume snapshot is provisioned at thedesired backup time using a combination of thin-provisioning for atarget volume and a specific setting for the FlashCopy function toreduce the overall storage footprint. It should be appreciated that thedisclosed techniques are not limited to Storwize® or the FlashCopyfunction.

With reference to FIG. 5, a diagram 500 of an exemplary process forperforming a snapshot, according to an embodiment of the presentdisclosure, is illustrated. As is shown, as dirty blocks are writteninto an original logical unit number (LUN) or source volume 502, fileswith blocks containing backup data are pushed to a snapshot LUN ortarget volume 504. Specifically, at time T1+delta desired blocks (i.e.,dirty blocks) are selected from source volume 502 and are backed up totarget volume 504. Similarly, at time T2 desired blocks (i.e., dirtyblocks) are again selected from source volume 502 and are again backedup to target volume 504. It should be appreciated that blocks thatcontain data prior to the snapshot are not written from source volume502 to target volume 504 during the snapshot. That is, only data thathas changed (i.e., dirty blocks) are written from source volume 502 tothe target volume 504 during a snapshot.

With conventional merging of delta files, an entire volume isreconstituted and written to a single contiguous volume space. That is,a new copy of all delta files is generated for an entire originalvolume. I/O read operations are then performed on the new copy toretrieve desired information which generates a relatively large numberof writes and then some reads on the new copy. According to the presentdisclosure, only blocks that have been modified are maintained on abackup volume. When a specific file is requested from the backup volume,a read I/O operation is performed directly on the backup volume thatmaintains the dirty blocks. More specifically, a real-time operation isinitiated in which clean blocks are read from an original volume anddirty blocks are read from a backup volume. In this case, thereconciliation of many I/O writes to a secondary disk is avoided.

According to one embodiment of the present disclosure, a process tooptimize the backup and recovery workflows may include a user selectingto backup a workload (e.g., a cloud workload), which may include avirtual machine (VM), a set of VMs, and/or management subsystems. Filesrelated to workload to be backed up are enumerated in a file set ‘Ef’,with an enumeration of storage volumes ‘Ev’ that include data related tothe enumerated files being identified. For each storage volume in ‘Ev’ asize of a source volume ‘S’ is determined and a target volume ‘T’ (withan identical size of the source volume ‘S’) is provisioned. The factthat the target volume ‘T’ is a thin-provisioned volume reduces requiredI/O and enables faster backup time while minimizing impact on otherworkloads on shared storage. As the virtual disk does not expanddynamically, the actual capacity requirement is fixed and sufficient tocontain dirty blocks that occur.

A volume level clone (or snapshot) from a source volume ‘S’ to a targetvolume ‘T’ may be initiated with a specific snapshot feature thatindicates that any data to synchronize the volumes is not to be copied.For example, on Storwize® systems a volume FlashCopy property ‘copyrate’ may be set equal to zero to indicate that data to synchronizevolumes is not to be copied. As a result, the target volume ‘T’ onlyincludes mapping entries of dirty blocks for the source volume ‘S’ andthe dirty blocks, which results in minimizing I/O cost. That is, thetarget volume ‘T’ only includes any blocks that become dirty in thesource volume ‘S’. The target volume ‘T’ can then be mounted in thebackup management system and the dirty blocks of the enumerated files‘Ef’ may then be copied onto a backup medium (offsite, tape, additionalvolume, etc.).

Following copying of the dirty blocks of the enumerated files ‘Ef’ tothe backup medium, the target volume ‘T’ may then be unmounted anddeleted. Subsequent to the deletion of the target volume ‘T’, anindication is provided to the user that backup is complete. Given arestoration point, the restoration operation is straight-forward as thedirty blocks of the enumerated files ‘Ef’ may be copied directly fromthe backup medium onto the original source volume ‘S’. In contrast,using conventional approaches, additional steps to merge snapshots havebeen required that have incurred significant I/O (and time) in order tocomplete a restoration operation backup.

With reference to FIG. 6, an exemplary process 600 is illustrated thatimplements techniques for optimizing backup workflows according tovarious embodiments of the present disclosure. As one example, ahypervisor of management layer 64 (see FIG. 3) executing on processor 16of server 12 may implement process 600, which may take the form of oneor more program modules 42 (see FIG. 1).

Process 600 may, for example, be initiated in block 602 in response to auser requesting a backup of an associated VM. Next, in block 604,processor 16 identifies one or more files associated with the VM. Then,in block 606, processor 16 identifies one or more source volumesassociated with the one or more identified files. Next, in block 608,processor 16 provisions a respective target volume for each of thesource volumes.

As one example, the VM may have three files associated with a workloadof the VM and the three files may, for example, be associated with threedifferent source volumes. In this case, processor 16 provisions threetarget volumes, i.e., one target volume for each of the source volumes.In at least one embodiment, a size of each of the target volumescorresponds to a size of an associated source volume. For example,assume that a first source volume has a size of 256 TB, a second sourcevolume has a size of 64 TB, and a third source volume has a size of 128TB. In this case, a first target volume with a 256 TB size isprovisioned, a second target volume with a 64 TB size is provisioned,and a third target volume with a 128 TB size is provisioned. As anotherexample, the VM may have four files associated with a workload of the VMand the four files may, for example, be associated with two differentsource volumes. In this case, processor 16 provisions two targetvolumes. As yet another example, the VM may have five files associatedwith a workload of the VM and the five files may, for example, beassociated with a single source volume. In this case, processor 16provisions one target volume.

Then, in block 610, processor 16 copies dirty blocks (associated withthe files identified at block 604), from the source volume(s) to theirrespective target volume(s). In various embodiments, the copying isperformed in a snapshot mode that prevents an update to the sourcevolume(s) during the snapshot mode. Next, in block 612, processor 16mounts the target volume(s) in the backup system, and the dirty blocksare copied from the target volume(s) to a backup medium. Then, indecision block 614, processor 16 determines whether the backup iscomplete. In response to the backup not being complete in block 614,control loops on block 614. In response to the backup being complete inblock 614, control transfers from block 614 to block 616. In block 616,processor 16 unmounts the target volume(s) and deletes the targetvolume(s). Next, in block 618, processor 16 sends a backup completenotification to the user to inform the user that the backup wassuccessful. Following block 618 process 600 terminates in block 620until a next backup request is received.

With reference to FIG. 7, a process 700 that implements techniques foroptimizing recovery workflows according to various embodiments of thepresent disclosure is illustrated. Specifically, process 700 restores aVM using backup data retrieved from a backup medium. As one example, ahypervisor of management layer 64 (see FIG. 3) executing on processor 16of server 12 may implement process 700, which may take the form of oneor more program modules 42 (see FIG. 1).

Process 700 may, for example, be initiated in block 702 in response to auser requesting a restoration of a VM. Next, in block 704, processor 16receives a restoration point for the VM that is to be restored. Then, inblock 706, processor 16 copies dirty blocks associated with therestoration point from the backup medium to one or more appropriatesource volumes. Following block 706 control transfers to block 708,where process 700 terminates until a next restore request is received.

It should be appreciated a restore operation according to the presentdisclosure does not require any ‘merge’ operations. That is, a restoreoperation according to the present disclosure only requires a singlecopy move operation for each file to be restored. When a specific fileis requested from a backup volume, a read I/O operation is performeddirectly on the backup volume that maintains the dirty block. That is, areal-time operation is initiated in which clean blocks are read from (acopy of) an original volume and dirty blocks are read from a backupvolume. In this case, the reconciliation of many I/O writes to asecondary disk is avoided.

Accordingly, techniques have been disclosed herein that optimize backupand recovery workflows. In general, the disclosed techniques employcoarse-grained volume snapshots for virtual machine backup and restorewhile minimizing performance impact and virtual disk footprint.

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

While the invention has been described with reference to exemplaryembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular system,device or component thereof to the teachings of the invention withoutdeparting from the essential scope thereof. Therefore, it is intendedthat the invention not be limited to the particular embodimentsdisclosed for carrying out this invention, but that the invention willinclude all embodiments falling within the scope of the appended claims.Moreover, the use of the terms first, second, etc. do not denote anyorder or importance, but rather the terms first, second, etc. are usedto distinguish one element from another.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below, if any, areintended to include any structure, material, or act for performing thefunction in combination with other claimed elements as specificallyclaimed. The description of the present invention has been presented forpurposes of illustration and description, but is not intended to beexhaustive or limited to the invention in the form disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the invention.The embodiments were chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A computer program product for backing up aworkload in a virtual environment, the computer program productcomprising: a computer-readable storage device; and computer-readableprogram code embodied on the computer-readable storage device, whereinthe computer-readable program code, when executed by a processor,configures the processor to: identify one or more files that areassociated with the workload; identify one or more source volumes thatinclude the one or more files; provision a respective target volume foreach of the one or more source volumes identified; copy in a snapshotmode that prevents an update to the one or more source volumes duringthe snapshot mode only dirty blocks from each of the one or more sourcevolumes to its respective target volume; and copy the dirty blocks fromeach target volume to a backup medium.
 2. The computer program productof claim 1, wherein the copying in a snapshot mode includes copying thedirty blocks utilizing a hardware-assisted volume snapshot.
 3. Thecomputer program product of claim 2, wherein the computer-readableprogram code, when executed by the processor, further configures theprocessor to: set a ‘copy rate’ property for the hardware-assistedvolume snapshot equal to zero to indicate that data to synchronize thesource and target volumes is not to be copied.
 4. The computer programproduct of claim 1, wherein the computer-readable program code, whenexecuted by the processor, further configures the processor to: unmountand delete each target volume subsequent to copying the dirty blocksfrom each target volume to the backup medium.
 5. The computer programproduct of claim 1, wherein the computer-readable program code, whenexecuted by the processor, further configures the processor to:provision each target volume with a same size as an associated one ofthe one or more source volumes.
 6. The computer program product of claim1, wherein the computer-readable program code, when executed by theprocessor, further configures the processor to: restore the one or morefiles to the one or more source volumes using the dirty blocks from thebackup medium.
 7. The computer program product of claim 1, wherein theone or more source volumes correspond to a single source volume having acorresponding single target volume that is a thin-provisioned volume. 8.A data processing system, comprising: a memory; and a processor coupledto the memory, wherein the processor is configured to: identify one ormore files that are associated with the workload; identify one or moresource volumes that include the one or more files; provision arespective target volume for each of the one or more source volumesidentified; copy in a snapshot mode that prevents an update to the oneor more source volumes during the snapshot mode only dirty blocks fromeach of the one or more source volumes to its respective target volume;and copy the dirty blocks from each target volume to a backup medium. 9.The data processing system of claim 8, wherein the copying in a snapshotmode includes copying the dirty blocks utilizing a hardware-assistedvolume snapshot.
 10. The data processing system of claim 9, wherein theprocessor is further configured to: set a ‘copy rate’ property for thehardware-assisted volume snapshot equal to zero to indicate that data tosynchronize the source and target volumes is not to be copied.
 11. Thedata processing system of claim 8, wherein the processor is furtherconfigured to: unmount and delete each target volume subsequent tocopying the dirty blocks from each target volume to the backup medium.12. The data processing system of claim 8, wherein the processor isfurther configured to: provision each target volume with a same size asan associated one of the one or more source volumes.
 13. The dataprocessing system of claim 8, wherein the processor is furtherconfigured to: restore the one or more files to the one or more sourcevolumes using the dirty blocks from the backup medium.